Watermelon is very cooling and good for Pitta. I understand that according to Chinese Medicine, the seeds are extremely cooling. Once one gets over the programming that the seeds are to be spit out, the crunch is actually enjoyable… like popcorn!
Watermelon is also, according to Chinese Medicine, very purifying… flushing out all sorts of toxins. They say that eating a large amount can result in a great excretion of fluids at first (even loose stools) which are Pitta and toxins. But then, everything normalizes as the Pitta disperses.